In an existing air-conditioning system that includes a plurality of air-conditioning apparatuses, each air-conditioning apparatus individually operates such that its own control target value is achieved, and normally, the air-conditioning apparatuses do not cooperate with each other. Here, the plurality of air-conditioning apparatuses include, for example, a direct expansion type air-conditioning apparatus and a floor cooling and heating apparatus using hot water and cold water. As described above, each of the direct expansion type air-conditioning apparatus and the floor cooling and heating apparatus included in the air-conditioning system operates such that the room temperature measured by each air-conditioning apparatus approaches a target temperature set by a user. Thus, the proportion of the load borne by each air-conditioning apparatus in the entire load required in an air-conditioned space is uncertain. Here, in the case of achieving the same temperature in the same environment, power consumption of the entire air-conditioning system varies depending on the proportion of the load borne by each air-conditioning apparatus. Patent Literature 1 discloses an air-conditioning system that creates an operation plan for a plurality of air-conditioning apparatuses such that power saving is achieved and in which the plurality of air-conditioning apparatuses operate according to the created operation plan. In Patent Literature 1, an operation plan that minimizes or maximizes an objective function is created on the basis of mathematical programming.